The present invention relates to an improved collapsible frame structure for use on an outdoor sunshade or parasol which is equipped with a minor extension arm coupled to a main runner of a main mast and a main extension arm in pivotal connection to a top retainer of the main mast at one end and to a lower end of a secondary stretching strut at the other end. The main extension arm and the minor extension arm are mutually coupled to each other at their middle points. The secondary stretching strut can be further pivotally coupled to an extended pivot end of either the minor runner or the top notch of the sunshade or parasol so as to permit the sunshade to be extended in an easier and smoother manner when the main runner is pushed up or pulled down.
Referring to FIG. 1, a conventional collapsible frame structure 1 of a sunshade or parasol is made up of a plurality of supporting ribs 10 respectively in pivotal coupling to a top notch 11 at the top end and sewn to the peripheral edge of the canopy 12 of the sunshade and parasol at the other end. The supporting ribs 10 are pivotally supported by a plurality of stretching ribs 15 which are coupled to a lower runner 13 at one end and connected to a pivot member 14 at the middle of each supporting rib 10 at the upper end. There are a main mast 16 having a main runner 160 slidable thereon, a main extension arm 17 and a minor extension arm 18 that are in cross connection to each other. The main runner 160 is in pivotal engagement with one end of the minor extension arm 18 which is in pivotal connection to the top notch 11. There is a secondary stretching strut 19 having one end in pivotal connection to the main extension arm 17 and the other end in pivotal engagement with one of the stretching ribs 15. Thereby the actuation of the main runner 160 can make the canopy 12 of the sunshade extended or collapsed.
Such a prior art frame structure has following disadvantages in practical operation:
1. The force exerted to the main runner 160 on the main mast 16 is directly transmitted to the secondary stretching strut 19 and one of the stretching ribs 15 linearly and not applied to the minor runner 160, making the opening and collapse of the canopy 12 with more effort wasted in vain.
2. The secondary stretching strut 19 and its associated stretching rib 15 are subject to excessive force when pushed and pulled, resulting in easy deformation of the frame structure in operation.
The primary object of the present invention is to provide an improved frame structure for use on a sunshade which is equipped with a secondary stretching strut in pivotal connection to either a top notch or a minor runner at one end and in pivotal connection to a the main extension arm at the other end. The secondary stretching strut is pivotally coupled to an extended pivot end of either the minor runner or the top notch so as to permit the sunshade or parasol to be extended or collapsed in an easier and smoother manner.
Another object of the present invention is to provide an improved frame structure which is provided with a secondary stretching strut either coupled to the minor runner or the top notch so as to make the applied force to be kept in a linear direction to prevent the secondary stretching strut and its associated stretching rib from being deformed by improper force.